Stitch controller

ABSTRACT

The present invention comprises externally accessible control means operatively connected to cam actuated kinematic linkages in sewing machines which impart precise longitudinal and transverse movements relative to the needle to material being stitched to permit separate variations to be made in the magnitude of the longitudinal or transverse movements without placing the sewing machine in an inoperable condition.

United States Patent Bianghi [4 1 Sept. 19, 1972 154] STITCH CONTROLLER Inventor: Nereo Bianghi, Pavia, Italy Assignee: Necchi S.p.A.

Filed: April 6, 1970 Appl. No.: 25,659

Foreign Applicatlon Priority Data Apr. 14, 1969 Italy 32409A/ 69 US. Cl. ..1 12/70 Int. Cl. ..D05b 3/04 Field of Search ..112/70, 72, 65, 19, 102, 112,

References Cited UNITED STATES PATENTS 3/ 1962 Taketomi ..l12/204 3/1961 vigot elliun, 1 12/205 2,969,755 1/1961 Reece ..1 12/70 X 2,428,321 10/1950 Smith ..l12/70 2,226,139 12/1940 Reilly ..l l2/70 583,422 5/1897 Towns et al. ..l l2/205 Primary Examiner-H. Hampton Hunter Attorney-Stevens, Davis, Miller & Mosher l 5 7] ABSTRACT 9 Claims, 4 Drawing Figures Ii D 5 V v f i f 27 Z6 Z5 12 25 71 5 "-32 PATENTEDSEPWIBYZ 3.691.969

SHEET 1 OF 2 3 271420 22 2.9 3010 23 I l mm i 5 mm H j r //V 4 J 5 5 FIG. 3

INVENTOR NEREO BIANCHI TTORNEYS STITCH CONTROLLER The present invention refers to'a device for adjusting the magnitude of the material displacements in sewing machines making a series of stitches. Particularly, the

transversely relative to the needle arm, in order to cause the fabric to take the consecutive positions, relative to the fixed needle, which are necessary for obtaining .the sewing pattern desired. Movement of the presser foot. clamp assembly is caused by a cam which can be replaced by other cams in order to obtain different patterns of stitches from the same machine. It is also possible to make variations in the stitching pattern which are similar to each other but of different sizes and to do this using the same cam.

This is possible, at the present state of the art, by varying the arrangement of a few members .in the kinematic control linkage placed between the cam and the clamp. Said variationsare made with the machine idle by skilled operators who adjust linkage members placed inside the base of the machine, and which are not reachable when the machine is in operation. These members can be, for example, bolts which can be secured at different positions along the groove of a lever, provided in said kinematic linkage in order to vary its movement arm. The complexity of this operation is a considerable disadvantage in the use of the sewing machines of the type mentioned above and involves the employment of skilled operators and an increase in the machine idle time thus causing a decrease of the productivity. 7

The present invention eliminates these disadvantages by making the operation of adjustment of the magnitude of .the displacements of the presser foot clamp assembly simple and easy. The technical problem to be solved was that of providing control members which could be moved from the outside of the machine and which were operable also while the sewing machine was in use to vary the configuration of the kinematic linkages which transmit movements from the cam groove to the presser foot clamp assembly. Additionally the members of said linkages had to be extremely simple in order to make the variations of their configuration quickly and to reduce forces of inertia developing owing to the quick oscillations of the same linkage members.

The present invention provides a solution to said technical problem and is a device having two sets of kinematic linkages, each formed by a cam follower for following the cam grooves, a shaft caused to oscillate by said carn follower, a number of rods substantially parallel to each other, a first group which is fixed to said shaft perpendicular to it and a second group which is fixed to-a block oscillating axially about an axis substantially parallel to said shaft, a limiting member enclosing both groups of said rods and sliding along them and being adapted for'transmitting to the second group of them the oscillations received from the first group, an arm fixed to the limiting member and connectable to the presser foot assembly clamp and control means operable from the outside of the machine to cause each of the limiting members to slide along said rods in order to vary the magnitude of the movements transmitted to the presser foot clamp assembly.

The device comprising the invention will now be described according to a preferred embodiment, illustrative and not restrictive of the invention, as shown by the attached drawings, in which:

FIG. 1 is a front view in partial section machine to which the device is applied;

FIG. 2 is a perspective view of the whole device;

FIG. 3 shows in partial section a magnified part of FIG. 2 and FIG. 4 shows the arrangement on the machine frame of the device drive members of FIG. 2.

The sewing machine shown in the drawings is a sewing machine adapted for producing a series of barshaped stitches on the fabric for reinforcing stitching of a sewing previously executed. The stitches of each series are made accordingto a predetermined cycle.

In FIG. 1 the above-mentioned sewing machine is designated by the numeral 10. The machine comprises a sub-base 11 for resting or mounting the machine on a frame or table (not shown) and a housing consisting of a'first vertical end wall '13 rising from one side of said sub-base, a horizontal top wall 14 connected at one end to wall 13, a second vertical wall 15 depending from the other end of the horizontal wall, a footed vertical wall 7 spaced between walls-l5 and 13, a generally L- shaped wall 6 spaced below wall 14 and parallel thereto and extendingfrom wall 7 to wall 15. Vertical front and back panels (not shown) complete the enclosing of the upper part of the housing just described. The lower part of the housing comprises a work table 5 extending under the upper part of the housing, to the lower portion of wall 13, an L-shaped bottom wall 12 rising from the other side of sub-base 11 and extending under work table 5 in spaced relationship and a hinged end plate 27 providing access to the shuttle compartment. As with the upper part of the housing, vertical front and back panels (not shown) complete the enclosing of the lower part of the housing. The front and back panels for both parts of the housing may be separate or integrally formed.

The upper part of the housing encloses the sewing needle assembly and the principal drive mechanism for the machine. The needle assembly comprises a needle 17 mounted in the lower end of needle bar 16 mounted for vertical oscillations along its axis through bushings 18 and 19 mounted in the ends of walls 6 and 14 respectively. The needle bar oscillates by the known system of a connecting rod 8 attached at its lower end to the bar 16 and at the upper end to crank 9 which is rotated by the drive mechanism. The drive mechanism comprises a main shaft 20 journaled in bushings 21 and 22 keyed into extension 21' and 22 on wall 6 and bushing 23 mounted in wall 13. The shaft 20 is rotated by an external source (not shown) but indicated at 4. A pitman 24,- placed into shaft 20, transmits, in a known manner, reciprocating motion'to shaft 25 mounted in the lower portion of said housing and having shuttle 26 at one end. End plate 27 is pivotally mounted on pin 28 to provide access to shuttle 26 for the usual operations of setting and bobbin substitution.

The'cam means of the invention comprises a disk 32 with a first eccentric cam groove 33 in its upper surface and a second eccentric cam groove 34 in theundersurface. Disk 32 is secured to the lower end of a vertical shaft 31 which is journaled in an extensionon the end of work table opposite the end under which the shuttle 26 is positioned. Rotation of vertical shaft 31 is derived from-shaft by means of a helical gear affixed to the upper end of vertical shaft 31, said helical gear 30 being in mesh with endless screw 29 fastened to shaft 20.

The first kinematic linkage comprises a cam follower, a vertical shaft attached thereto at the lower end and two groups 'of parallel rods and associated elements operatively connected to the upper end of the vertical shaft. The cam follower 35 comprises a roller 36 rotatably mounted inv one end of a lever 37. The opposite end of lever 37 is fixed to the lower end of a vertical shaft 38 which has affixed to its upper end a block 39. Shaft 38 is parallel to shaft 31 and journaled in table 5. Block 39 contains two spaced recesses for the first group of parallel rods 40. Rods 40 extend outward from block 39 and are slidably fitted in as many slots of a cylindrical moment limiting member 41. The second group of parallel rods comprises a rod 42, one end of which is inserted in a third slot of member 41 between rods 40 in slidable relationship with member 41. Rod 42 is fixed to block 43 which is secured to a vertical pin 44 which is free to rotate in a suitable seat in the work table 5. Pin 44 is parallel to and spaced from vertical shaft 38. An arm 45 is integral with block 43 in a depending manner and extends parallel to and under both groups of rods 40 and 42 and member 41. A pin 46 on the end of arm 45 opposite block 43 pivotally connects arm 45 to the end of another arm 47 which extends along the surface of work tableS toward needle 17.

Movement limiting member 41 is formed by a hollow cylinder 52 in which three cylindrical members 53 are placed with their axes parallel to the axis of said hollow cylinder 52. Each member 53 has a radial slot, positioned in correspondence with a radial slot in the surface of hollow cylinder 52 for slidably receiving the corresponding rod 40 or 42.

A second kinematic linkage similar to that of the first kinematic linkage begins from the second cam groove 34 in cam 32. A cam follower 63, following cam groove 34, is formed by a roller 64 rotatably mounted in one end of a lever 65. The other end of lever 65 is affixed to the lower end of a vertical shaft 66 substantially parallel to shaft 38 and journaled in table 5. Shaft 66 has at its upper end a block 67 affixed thereto. Projecting outwardly from block 67 and perpendicular to shaft 66 is a single rod 68. Rod 68 slidably passes through a center recess in the limiting member 69. Two additional rods 70 spaced from each other and parallel to rod 68 are carried by block 71 and slidably pass through member 69. Pin 72 on the underside of block 71 is free to rotate in a seat 3 in the machine. Integral with block 71 is arm '73 which has at its free end a pin 74 which engages a groove 75 in the under surface of arm 47.

The control means which can be actuated from outnected to each limiting member, which lever assem-' blies can be both moved simultaneously in the same direction and yet permit separate movement of each of said lever assemblies.

Limiting member 41 is pivotally fastened at least at its upper surface to one end of an arm 54. The arm 54 is pivotally joined at the opposite end by a pin to a second arm 56. Arm 56 can be pivotally moved about pin 57 which is fastened to the machine, the pin 57 being located between pin 55 and the extreme end portion 58 of arm 56 projecting from back cover of the machine. Portion 58 can be moved, in a horizontal slot 61 made in a plate 61 fastened to the back cover of the machine by means of screws 62. A resilient tooth 59 projecting from the underside of arm 56 is adapted to engage itself into grooves made out in the inner wall of plate 61. In such a way it is possible to fix arm 56 at different points of slot 61' of plate 61 and, consequently, the position of limiting member 41, sliding along pins 40 and 42 is changed relative to the axis of shaft 38.

Limiting member 69 has pivotally attached, at least on its .upper surface, an arm 76 which is pivotally'connected at its opposite end by a pin 77 to one end of another arm 78 which in turn can oscillate around a pin 79 placed in a seat in the machine, the pin 79 being adjacent the free end of arm 78. Arm 78 has on its free. end a sector gear 80 which is coupled with a second sector gear 81 formed on one end of another arm 82 which can be rotated around the pin 57 passing through arm 56. Arm 82 has an end 83 projecting from the back cover of the machine through slot 61". On the upper surface of arm 82 is tooth 84 adapted to be engaged into the grooves 60 in plate 61. In such a way arm 82 can be fixed in different positions along a second horizontal slot 61 of plate 61 and consequently the position of member 69 sliding along pins 68 and is changed relative to the axis of shaft 66.

An arc-shaped member 49 (FIG. 1) is fastened on arm 47 by means of screws 48, and carries at the opposite end a presser-foot 50, the'arm 47 and foot 50 providing a clamp for the fabric. The foot 50 can be moved vertically against the action of a leaf spring 51 relative to member 49 (in a known way not represented in detail in the drawings nor forming a part of this invention). Thus, under the action of said spring 51, the foot 50 biases the fabric against the end of rod 47 in a clamping action for the sewing. When, as described above, the foot 50 is raised relative to arm 47, the clamping action is removed and the operator may position fabric between said arm 47 and said foot 50 for subsequent sewing operations.

From the above description of the invention it is easily noted that the eccentricities of the cam grooves 33 and 34 of cam 32 produce axial oscillations of the corresponding shafts 38 and 66. These oscillations in'turn result in arcuate oscillations of the limiting members 41 47 toward and away from needle 17. The oscillations of block 71 and its arm 73 result in alternating movement ,of arm 47 transverse to the longitudinal movement produced by block 43. The longitudinal and transverse displacements of arm 47 are followed by presse'rfoot 50 which is integral with said arm through arc-shaped member '49 being fixed by screws 48 to the same arm 47 and therefore also to the fabric to be sewn which is clamped "between arm 47 and presser-foot 50. Movement of arm 56 in slot 61' moves limiting member 41 toward or away form pin 44 which increases or decreases, respectively, the length of arcuate movement of arm 45. This in turn increases or decreases the length of movement of arm 47 relative to needle "17 thus producing stitches more separated from each other or closer together. Movement of arm 82 similarly is translated through limiting member 69 to arm 47 and decreases or increases the transverse movement of arm 47 relative to needle 17 thus producing stitches of more narrow width or of greater width.

The pattems of sewing or stitching to 'be executed on the fabric vary according to the type of the cam mounted on the machine and, owing to the adjusting device shown, the same cam can be used to provide similar types of stitches but of different widths and/or at different intervals.

What is claimed is:

1. A sewing machine for producing a series of stitches of a predetermined type comprising a housing and work table, needle and bobbin means, and drive means, material holding means to controllably position material under said needle, cam means, two kinematic linkages actuated by said cam means and placed between said cam means and said material holding means to give to the latter transverse and longitudinal movements respectively and separately in compliance with said cam means, each of said kinematic linkages comprising a cam follower, a vertical shaft caused to oscillate axially about its axis by said cam follower, a plurality of rods substantially parallel to each other, a first group of saidrods being fixed to said shaft perpendicular to it and a second group of said rods being fixed to a block oscillating axially about an axis substantially parallel to and spaced from said shaft, a movementlimiting member slidably enclosing both groups of said rods and adapted to transmit to the second group of rods the oscillations received from said first group of rods; an arm fixed to the second group of rods of each linkage and connectable to the material holding means to provide transverse and longitudinal movements respectively to said material holding means as a translation of the oscillation of said respective groups of rods, and control means operable from the outside of said housing and connected to each of said limiting elements to controllably slide each element along its respective groups of said rods in order to vary the amplitude of the motion of said respective arm nonnally transmitted via said arm to the material holding means.

2. The sewing machine according to claim 1 wherein each of said limiting elements is formed by a hollow cylinder in which three cylindrical elements are placed, their axes being parallel to the axis of said hollow cylinder and having radial slots placed in correspondence with as many slots made out in the lateral surface of the same hollow cylinder.

3. The sewing machine according to claim 1 wherein said control means comprises a first lever means pivotally mounted within the housing of said machine and articulately connected to said limiting member imparting longitudinal movement to said material holding means relative to said needle, a second lever means pivotally mounted within the housing of said machine and articulately connected to said limiting member imparting transverse movement to said material holding means relative to said needle, and amplitude variation control means on said machine adapted to be selectively engaged by each of said lever means.

4. The sewing machine according to claim 3 wherein said first lever means comprises a first arm having one portion slidably projecting from said housing and. the other portion pivotally mounted along its length within said housing and a second arm pivotally fixed at one of its ends to the end of said other portion of said first arm and pivotally fixed at the other of its ends to the limiting member of said linkage operatively moving said material holding means in longitudinal amplitude'relative to said needle whereby movement of said first arm of said first lever means is mechanically translated into a linear displacement of said limiting member on said linkage to vary the amplitude of motion of said member. a I

5. The sewing machine according to claim 3 wherein said second lever-means comprises a first arm having one portion projecting from said housing and the other portion pivotally mounted along its length within said housing parallel to and spaced below said first lever means, and having a sector gear formed on the end thereof, a second arm pivotally mounted along its length at a position within said housing spaced from the pivotal mounting of said first arm, said second ann having at one end a sector gear engaging the sector gear on said first arm, the other end of said second arm being pivotally fixed to one end of a third arm, said third arm being pivotally fixed at the end away from said second arm to the limiting member of said linkage operatively moving said material holding means in transverse amplitude relative to said needle whereby movement of said first arm of said second lever means is mechanically translated into a linear displacement of said limiting member on said linkage to vary the amplitude of motion of said member.

6. The sewing machine according to claim 3 wherein said amplitude variation control means comprises a plate affixed over an opening in said housing, a pair of spaced horizontal slots in said plate to slidingly receive the end portions of said first and second lever means projecting therethrough and a plurality of stops on said plate between said slots and equally spaced therealong, said first and second lever means each having resilient means on said end portions to selectively engage any one of said stops thereby imparting a controlled variation in the amplitude of said respective limiting membets.

7. In a sewing machine producing a series of stitches of a predetermined type and including shiftable means for holding the material to be sewn in which cam means and kinematic linkages are provided to move the means holding the material to be sewn in repetitive transverse and longitudinal directions relative to the sewing needle in accordance with the stitching pattern established by said cam means, control means operable from the outside of the sewing machine and connected to each of said kinematic linkages to selectively vary the amplitude of motion of each of said linkages to alter the magnitude of the transverse and/or longitudinal movements transmitted to the material holding means by said cam means; comprising a first lever means pivotally mounted within the housing of said machine and articulately connected to said linkage imparting longitudinal movement to said material holding means relative to said needle, a second lever means pivotally mounted within the housing of said machine and articulately connected to said linkage imparting transverse movement to said material holding means relative to said needle, and amplitude variation control means on said machine adapted to be selectively engaged by each of said lever means; wherein said first lever means comprises a first arm having one portion slidably projecting from said housing and the other portion pivotally mounted along its length within said'housing and a second arm pivotally fixed at one of its ends to the end of said other portion of said first am and pivotally fixed at the other of its ends to the member of said linkage operatively moving said material holding means in longitudinal amplitude relative to said needle, whereby movement of said first arm of said first lever means is mechanically translated into a linear displacement of said member on said linkage to vary the amplitude of motion of said member.

8. In a sewing machine producing va series of stitches of a predetermined type and including shiftable means for holding the material to be sewn in which cam means and kinematic linkages are provided to move the means holding the material to be sewn inrepetitive transverse and longitudinal directions relative to the sewing needle in accordance with the stitching pattern established by said cam means, control means operable from the outside of the sewing machine and connected to each of said kinematic linkages to selectively vary the amplitude of motion of each of said linkages to alter the magnitude of the transverse and/ or longitudinal movements transmitted to the material holding means by means comprises a first arm having one portion projecting from said housing and the other portion pivotally mounted along its length within said housing parallel to and spaced behind said first lever means and having a sector gear formed on the end thereof, a second arm pivotally mounted along its length at a position within said housing spaced from the pivotal mounting of said first arm, said second arm having at one end a sector gear engaging the sector gear on said first arm, the other end of said second arm being pivotally fixed to one end of a third arm, said third arm being pivotally fixed at the end away from said second ar m to the member of said linkage operatively moving said material holding means in transverse amplitude relative to said needle whereby movement of said first arm of said second lever means is mechanically translated into a linear displacement of said member on said linkage to vary the amplitude of motion of said member.

9. In a sewing machine producing a series of stitches of a predetermined type and including shiftable means for holding the material to be sewn in which cam means and kinematic linkages are provided to move the means holding the material to be sewn in repetitive transverse and longitudinal directions relative to the sewing needle in accordance with the stitching pattern established by said cam means, control means operable from the outside of the sewing machine and connected to each of said kinematic linkages to selectively vary the amplitude of motion of each of said linkages to alter the magnitude of the transverse and/or longitudinal movements transmitted to the material holding means by said cam means; comprising a first lever means pivotally mounted within the housing of said machine and articulately connected to said linkage imparting longitudinal movement to said material holding means relative to said needle, a second lever means pivotally mounted within the housing of said machine and articulately connected to said linkage imparting transverse movement to said material holding means relative to said needle, and amplitude variation control means on said machine adapted to be selectively engaged by each of said lever means; wherein said amplitude variation control means comprises a plate affixed over an opening in said housing, a pair of spaced horizontal slots in said plate to slidingly receive the end portions of said first and second lever means projecting therethrough and a plurality of stops on said plate between said slots and equally spaced therealong, said first and second 

1. A sewing machine for producing a sEries of stitches of a predetermined type comprising a housing and work table, needle and bobbin means, and drive means, material holding means to controllably position material under said needle, cam means, two kinematic linkages actuated by said cam means and placed between said cam means and said material holding means to give to the latter transverse and longitudinal movements respectively and separately in compliance with said cam means, each of said kinematic linkages comprising a cam follower, a vertical shaft caused to oscillate axially about its axis by said cam follower, a plurality of rods substantially parallel to each other, a first group of said rods being fixed to said shaft perpendicular to it and a second group of said rods being fixed to a block oscillating axially about an axis substantially parallel to and spaced from said shaft, a movement-limiting member slidably enclosing both groups of said rods and adapted to transmit to the second group of rods the oscillations received from said first group of rods; an arm fixed to the second group of rods of each linkage and connectable to the material holding means to provide transverse and longitudinal movements respectively to said material holding means as a translation of the oscillation of said respective groups of rods, and control means operable from the outside of said housing and connected to each of said limiting elements to controllably slide each element along its respective groups of said rods in order to vary the amplitude of the motion of said respective arm normally transmitted via said arm to the material holding means.
 2. The sewing machine according to claim 1 wherein each of said limiting elements is formed by a hollow cylinder in which three cylindrical elements are placed, their axes being parallel to the axis of said hollow cylinder and having radial slots placed in correspondence with as many slots made out in the lateral surface of the same hollow cylinder.
 3. The sewing machine according to claim 1 wherein said control means comprises a first lever means pivotally mounted within the housing of said machine and articulately connected to said limiting member imparting longitudinal movement to said material holding means relative to said needle, a second lever means pivotally mounted within the housing of said machine and articulately connected to said limiting member imparting transverse movement to said material holding means relative to said needle, and amplitude variation control means on said machine adapted to be selectively engaged by each of said lever means.
 4. The sewing machine according to claim 3 wherein said first lever means comprises a first arm having one portion slidably projecting from said housing and the other portion pivotally mounted along its length within said housing and a second arm pivotally fixed at one of its ends to the end of said other portion of said first arm and pivotally fixed at the other of its ends to the limiting member of said linkage operatively moving said material holding means in longitudinal amplitude relative to said needle whereby movement of said first arm of said first lever means is mechanically translated into a linear displacement of said limiting member on said linkage to vary the amplitude of motion of said member.
 5. The sewing machine according to claim 3 wherein said second lever means comprises a first arm having one portion projecting from said housing and the other portion pivotally mounted along its length within said housing parallel to and spaced below said first lever means, and having a sector gear formed on the end thereof, a second arm pivotally mounted along its length at a position within said housing spaced from the pivotal mounting of said first arm, said second arm having at one end a sector gear engaging the sector gear on said first arm, the other end of said second arm being pivotally fixed to one end of a third arm, said third arm being pivotally fixed at the end away from said second arm to the limitiNg member of said linkage operatively moving said material holding means in transverse amplitude relative to said needle whereby movement of said first arm of said second lever means is mechanically translated into a linear displacement of said limiting member on said linkage to vary the amplitude of motion of said member.
 6. The sewing machine according to claim 3 wherein said amplitude variation control means comprises a plate affixed over an opening in said housing, a pair of spaced horizontal slots in said plate to slidingly receive the end portions of said first and second lever means projecting therethrough and a plurality of stops on said plate between said slots and equally spaced therealong, said first and second lever means each having resilient means on said end portions to selectively engage any one of said stops thereby imparting a controlled variation in the amplitude of said respective limiting members.
 7. In a sewing machine producing a series of stitches of a predetermined type and including shiftable means for holding the material to be sewn in which cam means and kinematic linkages are provided to move the means holding the material to be sewn in repetitive transverse and longitudinal directions relative to the sewing needle in accordance with the stitching pattern established by said cam means, control means operable from the outside of the sewing machine and connected to each of said kinematic linkages to selectively vary the amplitude of motion of each of said linkages to alter the magnitude of the transverse and/or longitudinal movements transmitted to the material holding means by said cam means; comprising a first lever means pivotally mounted within the housing of said machine and articulately connected to said linkage imparting longitudinal movement to said material holding means relative to said needle, a second lever means pivotally mounted within the housing of said machine and articulately connected to said linkage imparting transverse movement to said material holding means relative to said needle, and amplitude variation control means on said machine adapted to be selectively engaged by each of said lever means; wherein said first lever means comprises a first arm having one portion slidably projecting from said housing and the other portion pivotally mounted along its length within said housing and a second arm pivotally fixed at one of its ends to the end of said other portion of said first arm and pivotally fixed at the other of its ends to the member of said linkage operatively moving said material holding means in longitudinal amplitude relative to said needle, whereby movement of said first arm of said first lever means is mechanically translated into a linear displacement of said member on said linkage to vary the amplitude of motion of said member.
 8. In a sewing machine producing a series of stitches of a predetermined type and including shiftable means for holding the material to be sewn in which cam means and kinematic linkages are provided to move the means holding the material to be sewn in repetitive transverse and longitudinal directions relative to the sewing needle in accordance with the stitching pattern established by said cam means, control means operable from the outside of the sewing machine and connected to each of said kinematic linkages to selectively vary the amplitude of motion of each of said linkages to alter the magnitude of the transverse and/ or longitudinal movements transmitted to the material holding means by said cam means; comprising a first lever means pivotally mounted within the housing of said machine and articulately connected to said linkage imparting longitudinal movement to said material holding means relative to said needle, a second lever means pivotally mounted within the housing of said machine and articulately connected to said linkage imparting transverse movement to said material holding means relative to said needle, and amplitude variation control means on said machine adapted to Be selectively engaged by each of said lever means; and wherein said second lever means comprises a first arm having one portion projecting from said housing and the other portion pivotally mounted along its length within said housing parallel to and spaced behind said first lever means and having a sector gear formed on the end thereof, a second arm pivotally mounted along its length at a position within said housing spaced from the pivotal mounting of said first arm, said second arm having at one end a sector gear engaging the sector gear on said first arm, the other end of said second arm being pivotally fixed to one end of a third arm, said third arm being pivotally fixed at the end away from said second arm to the member of said linkage operatively moving said material holding means in transverse amplitude relative to said needle whereby movement of said first arm of said second lever means is mechanically translated into a linear displacement of said member on said linkage to vary the amplitude of motion of said member.
 9. In a sewing machine producing a series of stitches of a predetermined type and including shiftable means for holding the material to be sewn in which cam means and kinematic linkages are provided to move the means holding the material to be sewn in repetitive transverse and longitudinal directions relative to the sewing needle in accordance with the stitching pattern established by said cam means, control means operable from the outside of the sewing machine and connected to each of said kinematic linkages to selectively vary the amplitude of motion of each of said linkages to alter the magnitude of the transverse and/or longitudinal movements transmitted to the material holding means by said cam means; comprising a first lever means pivotally mounted within the housing of said machine and articulately connected to said linkage imparting longitudinal movement to said material holding means relative to said needle, a second lever means pivotally mounted within the housing of said machine and articulately connected to said linkage imparting transverse movement to said material holding means relative to said needle, and amplitude variation control means on said machine adapted to be selectively engaged by each of said lever means; wherein said amplitude variation control means comprises a plate affixed over an opening in said housing, a pair of spaced horizontal slots in said plate to slidingly receive the end portions of said first and second lever means projecting therethrough and a plurality of stops on said plate between said slots and equally spaced therealong, said first and second lever means each having resilient means on said end portions to selectively engage any one of said stops thereby imparting a controlled variation in the amplitude of motion of said linkage members. 